A method to determine relative production rates of the productive layers using quasi-steady flux temperature values measured along the wellbore is described, e.g., in: {hacek over (C)}eremenskij G. A. Prikladnaja geotermija, Nedra, 1977 p. 181. A disadvantage of this method is a low accuracy of the layers' relative flow rate determination resulting from the assumption of the Joule-Thomson effect constant value for different layers. In effect, it depends on the formation pressure and specific layer pressure values.